Traveling knife



April 10,1934. w FQWLE r AL 1,953,932

TRAVELING KNIFE Filed Feb. 28. 1935 Patented Apr. 10, 1934 burrs!) 'rrsssince composed of Jessie A. Fowle, Edna Fowle," Florence Haley, andWalter H. Fowle Application February 28, 1933, Serial N0. 658,902

3 Claims This invention relates to traveling knives, and moreparticularly to endless or belt traveling knives of l the type used forsplitting leather, rubber and the like, and methods of making the same.

One object of this invention is to provide a traveling knife with a rearor thrust edgeof such characteristics as to substantially prevent thedevelopment of cracks adjacent the thrust edge. thus permitting theknife to have a greater length of useful life with correspondingeconomy.

Another object of this invention is toprovide a traveling knife with aharder cutting edge than has heretofore been feasible in similar knives,and at the time to provide the thrust edge of the knife with suchcharacteristics as to substantially pre-- vent the development of cracksadjacent the thrust edge.

The above and other objects will appear from the following descriptionand appended claims forming a part of this specification.

In the accompanying drawing:

Fig. 1 illustrates a plan View of a portion of an endless or belt knifeused for splitting leather, rubber, and the like;

Fig. 2 is an edge view of Fig. 1;

Fig. 3 is a diagrammatic view of a knife being passed between heatedrollers to reduce the hardness of the thrust edge portion of the knife;and

Fig. 4 is a similar view of a knife being passed through molten lead toreduce the hardness of the thrust edge portion of the knife.

In the art of splitting leather, rubber and the like, it is usual tohave an endless or belt knife usually about 3 inches wide and inch thicksimilar to the portion of the knife 10 illustrated in the drawing. Theknife usually has a length of from 25 to 32 feet with the ends of thestrip forming the knife abutted together and brazed to form an endlessknife which extends around two pulleys usually about 30 inches indiameter and suitably spaced apart horizontally from each other to holdthe endless knife taut. One of the pulleys is power-driven to cause'theendless knife to travel continuously in one direction.

The upper part of the knife traveling between the two spaced pulleys isthe portion of the knife which is used for the splitting operation, thefront edge 11 of the knife constituting the cutting or splitting edgeand the rear or thrust edge 12 engaging or thrusting against a suitablefixed abutment to hold the knife in position against thrusting action ofthe leather or rubber against the cutting edge 11.

The traveling knife is made of very fine quality steel such as razorsteel and is given a suitable hardness or temper for the work to beperformed. Thecutting edge of the knife dulls rather rapidly and isrepeatedly resharpened until the width of the knife is reduced from itsoriginal width of 3 /4 inches to approximately 1 inches, when it 9 isdiscarded. Usually, however, long before the knife has worn down to awidth of 1 inches, cracks such as 13 develop at the thrust edge 12 ofthe knife progressively develop and extend toward the cutting edge 11 ofthe knife, thus re- 5 sulting in the knife usually being discarded longbefore it would be discarded there were no serious cracks present.

These cracks appear to result from strains and from the rubbing of thethrust edge 12 of the 70 knife agaist the fixed abutment previouslymentioned.

The steel used, usually contains from .60 to 1.20 per cent of carbon andmay contain alloy such for example as nickel and/or chromium and/orother metals. The range of temper given to the knife is usually from 35to 45 C-Scale Rockwell. Temper 46 is preferably used by expert operatorson hard dry leather. Tempers below 46 down to 35 are used, depending onconditions, the softer tempers being used on softer materials such assheepskin and also being used by the less skilled operators to avoiddanger of splitting the rear of the knife due to excessive strainsbrought on the knife.

We have discovered that by giving the portion of the knife extendingalong and adjacent the thrust edge 12, a temper suitably lower than thetemper of the cutting portion of the knife, the development of cracksadjacent the thrust edge is substantially prevented.

We have further discovered that by providing the portion of the knifeextending along and adjacent the thrust edge with a temper whichsubstantially prevents the development of cracks, the hardness of theportion of the blade extending along andadjacent the cutting edge of theblade can be stepped up to provide a cutting edge of increased hardness,which is a matter of great commercial importance, since it enables anincreased output of split leather or rubber to be obtained due to thecutting edge remaining sharp for a longer period of time beforerequiring resharpening. The less frequent resharpening also results inthe knife having a longer useful life, with cor- 5 responding economy.Knives made in accordance with our invention may be provided with thecutting portion from about 42 to 50 temper- C-Scale Rockwell.

We preferably provide the thrust portion of .110

the knife with a temper above 27 but preferably not above 35 temperC-Scale Rockwell. The thrust portion of the blade which is given thelow, anti-cracking temper is preferably a strip from about inch to aboutlinch in width ex-- tending along and adjacent the thrust edge. Theremainder of the width of the knife is given the desired higher cuttingtemper.

In practice, the entire knife is preferably given the desired highcutting hardness or temper in any desired way, and then the strip ofdesired width along the thrust edge 12 is given the desired, loweranti-cracking temper by suitable temper-drawing procedure, such .aspassing the strip adjacent the thrust'edge 12 between .rollers l4suitably heated, electrically or otherwise, or by passing it throughsuitably heated material 15 such as molten lead or the like.

The invention may be carried out in other specific ways than thoseherein set forth without departing from the spirit and essentialcharacteristics of the invention, and the present embodiments aretherefore to be considered in all respects as illustrative and notrestrictive, and all changes coming within the meaning and equivalencyrange of the appended claims are intended to be embraced therein.

We claim:

1. A band traveling knife of considerable width for splitting leather,rubber or the like comprising: a knife edge, a thrust edge, and a bodyintermediate said edges, said knife edge and the portion of the body atand extending back a considerable distance from the knife edge having asuitable substantially-uniform cutting hardness greatly less thanglass-hard, and a portion of the body at and extending back from thethrust edge having substantially less hardness than the knife edge,whereby development of cracks adjacent the thrust edge is substantiallyprevented.

2. A band traveling knife of considerable width for splitting leather,rubber or the like comprising: a knife edge, a thrust edge, and a bodyintermediate said edges, said knife edge and the portion of the body atand extending back a considerable distance from the knife edge having asuitable substantially-uniform cutting hardness greatly less thanglass-hard but substantially greater than 46 C-Scale Rockwell, and aportion of the body at and extending back a considerable distance fromthe thrust edge having substantially less hardness than 35 C-ScaleRockwell, whereby development of cracks adjacent the thrust edge issubstantially prevented.

3. A band traveling knife of considerable width for splitting leather,rubber or the like comprising: a knife edge, a thrust edge, and a bodyintermediate said edges, said knife edge and the portion of the body atand extending back a considerable distance from the knife edge having asuitable substantially-uniform cutting hardness greatly less thanglass-hard and at least 35 C- Scale Rockwell, and a portion of the bodyat and extending back from the thrust edge having less hardness than theknife edge and substantially less than 35 but greater than 27 C'-ScaleRockwell, whereby development of cracks adjacent the thrust edge issubstantially prevented.

